Welcome to HVAC-Talk.com, a non-DIY site and the ultimate Source for HVAC Information & Knowledge Sharing for the industry professional! Here you can join over 150,000 HVAC Professionals & enthusiasts from around the world discussing all things related to HVAC/R. You are currently viewing as a NON-REGISTERED guest which gives you limited access to view discussions

To gain full access to our forums you must register; for a free account. As a registered Guest you will be able to:

Participate in over 40 different forums and search/browse from nearly 3 million posts.

Start by trying to block off the supply partially somehow and you will see that the amperage will decrease.

That is correct block off either the supply or return it doesnt matter. Fan motors are designed to do work, if they are not loaded they will not build sufficient speed to cool themselves.
Ever take a blower out of a replacement furnace and try and run it?
Sometimes they will overheat etc, block off the supply they build speed and drop amperage and run fine.

yup- 11 A FLA, 12.6 A measured, two different motors, two different meters.

If it is possible , it would be very interesting to see the performance characteristics of the motor or motors at your local motor repair shop . Provide them with all the information you have , and let them test the motors on the bench . If everything checks out , ie. not drawing FLA with NO LOAD , then you will be getting warmer to the solution . Worst case scenario , they should be able to provide you with more information as to what your problem is and maybe provide some testing equipment to help you . If the cant they will know someone who can .

Oh, and by the way, I just found out that the motor for the hydraulic pool cover burnt out as well. Has only been in two weeks and is used rarely for 30 seconds at a time. Coincidence, I think not.

Lets see..... that is 3 blower motors with a problem and now this motor too.
Sure would lead me to look a little closer at the power source. This may not be the problem but it sure warrants a closer look.

Lets see..... that is 3 blower motors with a problem and now this motor too.
Sure would lead me to look a little closer at the power source. This may not be the problem but it sure warrants a closer look.

Lets see..... that is 3 blower motors with a problem and now this motor too.
Sure would lead me to look a little closer at the power source. This may not be the problem but it sure warrants a closer look.

I did not notice the part about the pool cover motor burning out also. Just confirms what most of us are thinking-power supply.

Are the power system voltages to ground correct and closely balanced?
Any difference between neutral and ground?
Usually a system that loses its ground reference and begins to float doesn't burn up motors, though. You'd usually see funny arcing conduit joints and reports of people getting shocked. Or maybe dimming lights and that kind of stuff.

Some kind of intermittent loss of connection at a lug, a breaker stab, a loose busbar?

No neutral in unit. This has been an ongoing issue with consistent readings.